Several methods and apparatus for cutting slabs of cellular polymer materials have been disclosed in the prior art. Of particular interest is U.S. Pat. No. 5,534,208 (Barr). This patent discloses a continuous rotary method for surface shaping synthetic foams in which the foam is compressed between a smooth compression roller and a die roller having raised and recessed portions. The portions of the foam extruded into the recesses in the die roller are cut away by a blade. The compressed foam portions return to an uncompressed state after passing through the rollers. As a result, a mirror-image pattern to the pattern on the surface of the die roller is cut on the surface of the foam. It can be difficult to produce troughs with flattened bottom surfaces using this rotary method. Moreover, the depth of cut is proportionate to the die roller pattern depth. See also, U.S. Pat. No. 5,688,538.
Heretofore, it has been difficult to form foam parts having deep cut portions, e.g., up to 80% of the thickness of the foam slab, using the continuous cutting method of the '208 patent. Such deep cut portions with relatively straight and relatively vertical side walls are also difficult to process. Thus, apparatus and methods for producing such foam parts are desired.